Currently, standardized and commercially deployed radio access technologies are proliferated. Such radio access technologies include the Global System for Mobile communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE), General Packet Radio System (GPRS), Wide-band Code Division Multiple Access (WCDMA), Long Term Evolution (LTE) systems, Wireless Local Area Networks (WLAN), CDMA 2000 and others.
Positioning in wireless communication systems comprising these or other technologies can be performed in many different ways. A typical approach is that a request for positioning is provided. If the positioning information is not already available, some kind of measurement may be performed, and positioning data may be reported to a node responsible for the actual positioning.
Fingerprinting positioning algorithms operate by creating a radio fingerprint for each point of a fine coordinate grid that covers the Radio Access Network. The fingerprint may e.g. comprise the cell IDs that are detected by the terminal, in each grid point, or quantized path loss or signal strength measurements, with respect to multiple radio base stations, performed by the terminal, in each grid point.
Whenever a position request arrives to the positioning method, a radio fingerprint may be computed, based on various parameters which needs to be measured. Thereafter the corresponding grid point is looked up and reported. This requires that the point is unique. A major problem with this approach is that extensive surveying needs to be performed when the fingerprinting database is created. Nevertheless, a possible approach for generating fingerprinted positions may be to perform an extensive surveying operation that performs fingerprinting radio measurements repeatedly for all coordinate grid points of the Radio Access Network. This approach comprise however the disadvantage of becoming substantial, also for small cellular networks. Further, the radio fingerprints are in some instants e.g. signal strength and path loss, sensitive to the orientation of the terminal, a fact that is particularly troublesome for handheld terminals. For fine grids, the accuracies of the fingerprinted positions therefore become highly uncertain.
Further, certain approaches for generating fingerprinted positions may result in positioning data that does not comply with the available standards of today. Updating of different standards is a time-consuming and complex task and the request for using the new positioning methods as soon as possible rushes the implementation of the improvements. A general problem is thus that in order to allow for implementation of different improved positioning methods, reporting of positioning data has to be performed according to new manufacturer-specific non-standard protocols, which in turn limits the use to systems where all parts are provided by the same manufacturer.
Further, there is no measurements defined in LTE that specifically target positioning. As modulation schemes and sequences used in LTE are different from WCDMA, the measurement and positioning procedures used in WCDMA could not be used in LTE.